Antioxidants



Pat nted July 10,l945 2,330,129

UNITED STATES PATENT OFFICE ANTIOXIDANTS Frank R. Valentine, Jr., Nauzatuck, Coma, as-

siznor to United States Rubber Company, New York, N. Y., a corporation of New Jersey No Drawing. Original application January 29,

1943, Serial No. 413,975. Divided and this application February 24, 1944, Serial No. 523,749

, 7 Claims. (Cl. 260-808) This invention relatesto a new class of antiox- 4,4-di-(p-benzylphenylamino) dip yl r nidants or age-resisters for organic substances ate which tend to deteriorate by absorption of oxygen 4,4-di (phenylamino) 2,2'-dimethyl diphenyl from the air, e. g., rubber or allied gums, unsatucarbonate rated fatty oils, such as unsaturated vegetable oils, 3,3'-d1- (naphthylamino) -2,2'-dichloro diphenyl essential oils, petroleum oils, and their derivatives carbonate such as gasolines, soaps, aldehydes, synthetic res- 4,4'-di-(p-isopropenylphenylamino) diphenyl carins, turpentine, insecticides such as derris root, bonate cube root and 'pyrethrum, and the like.- The ma- 3,3'-di-(p-allyl phenylamino) diphenyl carbonate terials are exceptionally useful as i'lex-improvers 10 4,4-di-(p-anisylamino) diphenyl carbonate or anti-flex cracking agents for vulcanized rub- -4,4'-di-(p-phenetylamino) diphenyl carbonate ber, such as tire treads, which undergo repeated 4,4'-di-(biphenylamino) -3,3'-dibromo diphenyl strains during use. carbonate This case is a division of my cope s applies- 3,3'-di-(p-phenoxy phenylamlno) diphenyl cartion Serial No. 473,975, filed January 29, 1943. bonate According to the invention the organic sub- 4,4'-di-(p-allyloxy phenylamino) diphenyl carstance is incorporated with a chemical having the bonate neral formula 2,2'-di-(p-chlorophenylamino) diphenyl carboni ate m1 Nil-MP0 i go 4,4'-di'-(p-phenylamino phenylamino) diphenyl carbonate Aryl-NH-aryiene0 3,3-di-(m-phenylamino phenylamino) diphenyl l carbonate where aryl and arylene each refer to an aromatic nucleus of the benzene, naphthalene, or biphenyl 2 tdimethylammo phenylammo) dlphenyl series. carbo a e The aryl and arylene nuclei may contain as lino phenylammo) diphenyl ca bonate substltuents amlkyl amenyl' 44'- di-(phenylamino)-2,2'-di-tertiary butyl diaryloxy, lkenyloxy. h Sewndary and phenyl carbonate tiary alkyl amino, secondary aryl amino, alkyl 4,4, d1 (pheny1amm0) d1 a1 h naphthy1 mercapto, etc. ul 1381 t h m bonate The following form a ven s ow enum- 1 bering used in the aryl nuclei of the compounds: (p tolylammo) d1 beta naphthy ca 0 4,4'-di-(napthylamino) 2,2'-diphenyl diphenyl carbonate m o O O 3 4,4'-di-(biphenylamino) 2,2'-dimethoxy di-al- 4 pha-naphthyl carbonate 0:0 In general, these carbonates may be prepared by passing phosaene into a solution or suspension 40 of the sodium salt of the phenol in a suitable a liquid. Generally, symmetrical carbonates are I a 0 made in this way, but, if a mixture of arylamino P O A phenols is used, as for example mixed phenylamino cresols, an unsymmetrical product will result. 5' h The following examples illustrate the invention, As specific examples, the following may be the parts being by weight given: Exsurm: 1

4,4'-di-(phenylamine) diphenyl carbonate r4,4'-di-(phenylamino) diphenyl carbonate may 3,3-di-(phenylamino) diphenyl carbonate be prepared by dissolving 5.6 grams of metallic 2,2'-di-(phenylamino) diphenyl carbonate sodium (0.244 mole) in 250 cc. of absolute alcohol 4,4'-di-(naphthylamino) diphenyl carbonate and adding 30 grams of 4-hydroxy diphenylamine 4,4'-di-(biphen'ylamino) diphenyl carbonate (0.162 mole). After the 4-hydroxy diphenyla- 3.3'-di- (p-tolylamino) diphenyl carbonate mine has dissolved, the alcohol is removed on the 4,4'-di-(o-tolylamino) diphenyl carbonate steam bath. Acetone cc.) is added and the suspension stirred and. cooled in an ice bath. Over a period of 30 minutes, 7.9 grams of phosgene (0.08 mole) is passed into the suspension and after the addition is complete, the stirring is con- EXAMPLE 2 Preparation of 4,4'-di-(beta-naphthylamino) diphenyl carbonate Para-hydroxy phenyl beta naphthylamine (50 grams), 0.21 mole, was dissolved in 500 cc. of acetone and 5.4 grams of sodium (0.232 mole) added. After the sodium has dissolved, grams. of phosgene (0.1 mole) was passed into the cooled, well stirred mixture. The mixture was then diluted with 500 cc. of water and the solid filtered, washed with water and dried. It weighed 33 grams. After crystallization from dilute acetone it melted at 170-171 C.

EXAMPLE 3 These materials have been found to be useful as preservatives for rubber. Thus, tests were made on the following compound:

Master batch Parts Pale crepe 100.0 Zinc oxide 10.0 Lithopone 60.00 Whiting 60.0 Sulfur 3.0 Tetramethyl thiuram monosulfide 0.15

To the master batch, 4,4'-di-(phenylamino) diphenyl carbonate and 4,4-di-(beta-naphthylamino) diphenyl carbonate were added in the proportion of 1 part to 100 partsof rubber. Cures were made for 10, 20, and 30 minutes at 25 pounds per square inch steam.- Th percent remaining tensile before and after ageing 96 hours under 300 pounds per square inch oxygen at 70 C. are as follows:

Control Chemical I Unac'nrl 100 100 A gnd 16 62 Control Chemical II Un a ed 100 100 Aged 16 w Chemical 1: 4,4 di (phenylamino) diphenyl carbonate.

Chemical II: 4,4'-di-(beta-naphthylamino) diphenyl carbonate.

The invention may be applied to the preservation of, broadly, natural rubber compositions as well as artificially-prepared rubber compositions, such as polychloroprene, olefine polysulildes, butadiene polymers, modified butadiene polymers (Buna N and Buna S), and including reclaims, and latices of such composition.

It is also to be understood that other desired filling and compounding ingredients may be incorporated along with the preservative, for example, in the case of rubber, there may be incorporated other accelerators, softeners, etc.

The antioxidant may be incorporated in any type of rubber composition, such as those used for automobile tires and tubes, hose, belting, sheet and thread rubber, rubberized fabrics, molded goods, boots and shoes, etc., whether vulcanized in a mold, in open steam, in hot air, or in the cold by the so-called acid process. The proportion of the antioxidant may vary from about 0.1% to 5%, although either smaller or greater proportions may be found useful. If the material to which it is added is a liquid such as rubber cement or an oil, the antioxidant may be dissolved therein in a suitable small proportion. The antioxidant may be incorporated into solid substances by milling or mastication, and prepared for incorporation into dispersions or solutions eitherv in powder, paste or solution form, or applied in such forms for incorporation by diffusion, to the surface of vulcanized or unvulcaniud rubber goods.

Havin thus described my invention, what I claim and desire to protect by Letters Patent is:

1. A method of retarding the deterioration of an organic substance which tends to deteriorate by absorption of oxygen from the air which comprises incorporating therein a compound having the general formula where aryl and arylene each refer to an aromatic nucleus selected from the class consisting of the benzene, naphthalene, and biphenyl series. 1

2. A method of preserving a rubber composition which comprises incorporating therein a 4,4-di-(arylamino) diaryl carbonate, in which the aryl radicals refer to an aromatic nucleus selected from the class consisting of the benzene, naphthalene, and biphenyl series.

3. An organic substance which tends to deteriorate by absorption of Oxygen from the air containing a compound having the general formula Aryl-NH-arylene-O C==O ArylNH-aryleneO where aryland arylene each refer to an aromatic nucleus selected from the class consisting of the benzene, naphthalene, and biphenyl series.

4. A rubber composition containing a compound having the general formula where aryl and arylene each refer to an aromatic nucleus selected from the class consisting of the benzene, naphthalene, and biphenyl series.

5. An organic substance which tends to deteriorate by absorption of oxygen from the air containing a 4,4'-di-(arylamino) diaryl carbonate, in which the aryl radicals refer to an aromatic nucleus selected from the class consisting of the benzene, naphthalene, and biphenyl series.

6. A rubber composition containing 4,4'-di- (phenylamino) diphenyl carbonate.

7. A rubber composition containing 4,4'-dl- (beta-naphthylamino) diphenyl carbonate.

FRANK R. VALENTINE, JR. 

